1. Field of the Invention
This invention relates to on-off sprinkler heads and, more particularly, to such a sprinkler head which is controlled by a temperature responsive element, such as a snap disc or a fusible alloy.
2. Description of the Prior Art
It has heretofore been proposed as shown in the patents to Mears, U.S. Pat. Nos. 3,757,866 and 3,812,914, to employ piston controlled valves which are controlled by pilot valves actuated by bimetallic temperature responsive discs, but these have not proven wholly satisfactory in use, because the contamination level to critical internal components can cause buildup of mineral and sludge deposits and thus, with a circuitous flow, as in U.S. Pat. No. 3,757,866, have caused difficulties which cannot occur in the structure of the present invention.
Mears, in U.S. Pat. No. 4,128,128, shows a diaphragm actuated sprinkler head in which the diaphragm carries a hollow cylindrical valve which is movable upwardly against the downward force of a spring 52 and which is actuated upwardly by water pressure available through the branch water passageway 42 and control passageway 46, when the pilot valve of the pilot valve assembly 40 is opened by the bimetalic disc 62. This structure is subject to contamination and buildup of mineral and sludge deposits.
Smith, in U.S. Pat. No. 2,026,916, shows a toilet flush valve which includes a valve body having a resilient tube 50 within a sleeve 53 slotted at 54 and 54a to communicate with a chamber 11 between interior body portions 16 and 17. A restricted bypass 18 is provided through the body portion 16 for restricted delivery of liquid into the chamber 11, as controlled by the setting of the valve 20 with respect to the tube 19. The resilient tube 50 has a tube flange 52 which is held at the bottom by the sleeve 53 against a ring 55 which engages a shoulder 17a, and at the top has a flange 51 which is held against the sleeve by a ring 60 threaded into a coupling 61 which is in turn threaded into the body portion 16. The tube 50 is normally held in closed position as shown in FIGS. 3 and 5, and in order to relieve the pressure in the chamber 11 and effective through the slots 54 and 54a on the exterior of the tube 50, a handle 41 on a rod 33 is provided for movement of a valve plug 30 from its seat 31 for discharge of liquid from the chamber 11 through a restricted opening 25 and a port 32 into the outlet passage 12. When the valve plug 30 returns to its seat, the pressure will build up and shut off flow through the tube 50. The Smith structure is complicated to assemble, has fluctuations in the system, does not have any response to excessive temperatures, and lacks the molded valve of applicant.
Comb, in U.S. Pat. No. 2,786,642, shows in FIGS. 1, 2 and 3, a pilot controlled hollow flexible or resilient tubular valve member 7 which engages a central rod 19 disposed between the inlet openings 15 at ingress port 3 in a sealing ring plate 16 and outlet opening 17 at egress port 5 in a sealing ring plate 18. The valve member 7 is described as located within pipe 1 and attached thereto by means of sealing rings 9 and 11. The pipe section 1 bounds, with the valve member 7, a fluid tight chamber 13 to which fluid is accessible at the ingress end through a conduit 23, the conduit 23 at the egress end being controlled by a valve 24 which has a plunger 25 actuated by a solenoid 27. When the valve 23 is open by actuation of the solenoid 27, fluid may flow to the egress port of the pipe to drop the pressure in the chamber 13 so that the tubular valve member 7 assumes a tubular shape permitting flow.
The other forms of the Comb disclosure in FIGS. 4 to 10, inclusive, are not relevant to the present invention.
Applicant has provided a positive attachment for the ends of the tubular valve member to overcome problems which may arise if the structure is inactive for a long period of time, and there is no suggestion in Comb of any temperature responsive control which is particularly suitable for reducing water damage by a sprinkler, nor of a compact temperature controlled valve of the character disclosed.